Make sure that Content Handled application can be connected multiple times.

mojo/application_manager/application_loader.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_APPLICATION_MANAGER_APPLICATION_LOADER_H_
 #define MOJO_APPLICATION_MANAGER_APPLICATION_LOADER_H_
 
 #include "base/memory/ref_counted.h"
 #include "mojo/application_manager/application_manager_export.h"
 #include "mojo/public/cpp/system/core.h"
 #include "mojo/services/public/interfaces/network/url_loader.mojom.h"
 #include "url/gurl.h"
 
 namespace mojo {
 
 class ApplicationManager;
 
 // Interface to allowing loading behavior to be established for schemes,
 // specific urls or as the default.
 // A ApplicationLoader is responsible to using whatever mechanism is appropriate
 // to load the application at url.
 // The handle to the shell is passed to that application so it can bind it to
 // a Shell instance. This will give the Application a way to connect to other
 // apps and services.
 class MOJO_APPLICATION_MANAGER_EXPORT ApplicationLoader {
  public:
   class MOJO_APPLICATION_MANAGER_EXPORT LoadCallbacks

[Aaron Boodman, 2014/11/18 23:46:15]

We don't need LoadCallbacks anymore. We can just use an actual base::Callback,
right?

[qsr, 2014/11/19 13:42:37]

Done.

       : public base::RefCounted<LoadCallbacks> {
    public:
-    // Register the requested application with ApplicationManager. If the
-    // returned handle is valid, it should be used to implement the
-    // mojo::Application interface.
-    virtual ScopedMessagePipeHandle RegisterApplication() = 0;
-
     // Load the requested application with a content handler.
     virtual void LoadWithContentHandler(const GURL& content_handler_url,
+                                        ScopedMessagePipeHandle shell_handle,
                                         URLResponsePtr url_response) = 0;

[DaveMoore, 2014/11/18 17:00:45]

I like this. It's a lot more like ApplicationLoader used to be before the
ContentHandler support was added.

 
    protected:
     friend base::RefCounted<LoadCallbacks>;
     virtual ~LoadCallbacks() {}
   };
 
-  // Implements RegisterApplication() by returning a handle that was specified
-  // at construction time. LoadWithContentHandler() is not supported.
-  class MOJO_APPLICATION_MANAGER_EXPORT SimpleLoadCallbacks
-      : public LoadCallbacks {
-   public:
-    SimpleLoadCallbacks(ScopedMessagePipeHandle shell_handle);
-    ScopedMessagePipeHandle RegisterApplication() override;
-    void LoadWithContentHandler(const GURL& content_handler_url,
-                                URLResponsePtr response) override;
-
-   private:
-    ScopedMessagePipeHandle shell_handle_;
-    ~SimpleLoadCallbacks() override;
-  };
-
   virtual ~ApplicationLoader() {}
 
   // Load the application named |url|. Applications can be loaded two ways:
   //
   // 1. |url| can refer directly to a Mojo application. In this case, call
   //    callbacks->RegisterApplication(). The returned handle should be used to
   //    implement the mojo.Application interface. Note that the returned handle
   //    can be invalid in the case where the application has already been
   //    loaded.
   //
   // 2. |url| can refer to some content that can be handled by some other Mojo
   //    application. In this case, call callbacks->LoadWithContentHandler() and
   //    specify the URL of the application that should handle the content.
   //    The specified application must implement the mojo.ContentHandler
   //    interface.
   virtual void Load(ApplicationManager* application_manager,
                     const GURL& url,
+                    ScopedMessagePipeHandle shell_handle,
                     scoped_refptr<LoadCallbacks> callbacks) = 0;
 
   // Called when the Application exits.
   virtual void OnApplicationError(ApplicationManager* manager,
                                   const GURL& url) = 0;
 
  protected:
   ApplicationLoader() {}
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_APPLICATION_MANAGER_APPLICATION_LOADER_H_